1. Field of the Invention
The present invention relates to an axial flow fan.
2. Description of the Related Art
FIG. 1 is a perspective view of a conventional axial flow fan 10. The axial flow fan 10 includes an outer frame 101, a plurality of stator vanes 102, and a base 103. The outer frame 101 is a hollow member provided with an intake vent and an exhaust vent. There is formed a diameter expanded part 101a and there are disposed the stator vanes 102 and the base 103 at the exhaust vent of the outer frame 101. The outer frame 101, the stator vanes 102, and the base 103 are integrally formed by injection molded resin.
In injection molding, one die is formed by combining two kinds of die parts, namely, a fixed die part and a movable die part. Melt resin is cast into the die and then is cooled. Thereafter, the cooled and solidified resin is taken out of the die. The outer frame 101, the stator vanes 102, and the base 103 are thereby formed as one member.
There are provided a plurality of seats 104 formed at parts where the diameter expanded part 101a and the stator vanes 102 are respectively joined. The seats 104 are positioned at blind portions when an integrally molded component having the outer frame 101, the stator vanes 102, and the base 103 is seen from a direction of being taken out of the die. When air is exhausted from the exhaust vent and hits the seats 104, there arise problems of noise generation, as well as decreases in volume of airflow and static pressure thereof.